Exhaust chamber for saddle-riding type vehicle

Abstract

An exhaust chamber is disposed in an exhaust passage through which exhaust gas from an engine passes. The exhaust chamber includes: an inner case having a chamber expansion region therein; and an outer case configured to cover a portion of the inner case. The inner case has a first inner case half and a second inner case half which are obtained by division into two parts, and is formed by the first inner case half and the second inner case half being joined to each other at an inner joining portion. The outer case has a first outer case piece and a second outer case piece which are spaced from each other. The first outer case piece and the second outer case piece are each joined to a portion, on an outer surface of the inner case, which portion is different from the inner joining portion.

What is claimed is: 
     
       1. An exhaust chamber, for a saddle-riding vehicle, disposed in an exhaust passage through which exhaust gas from an engine of the saddle-riding vehicle passes, the exhaust chamber comprising:
 an inner case having a chamber expansion region therein; and 
 an outer case configured to cover at least a portion of the inner case, the outer case being made of metal, wherein 
 the inner case has a first inner case half and a second inner case half which are obtained by division into two parts, and is formed by the first inner case half and the second inner case half being joined to each other at an inner joining portion, 
 the outer case has a plurality of outer case pieces that are spaced from each other, 
 each of the plurality of outer case piece is joined to a portion, on an outer surface of the inner case, which portion is different from the inner joining portion, and each of the plurality of outer case pieces are disposed over a first division surface of the first and the second inner case halves, and are joined to both of the inner case halves. 
 
     
     
       2. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 1 , wherein the outer case covers the inner case from an outer lateral side of a vehicle body. 
     
     
       3. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 1 , wherein the inner case includes a first portion covered by the outer case and a second portion which is not covered by the outer case. 
     
     
       4. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 1 , wherein a heat insulation space is formed between the inner case and the outer case. 
     
     
       5. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 1 , wherein the outer case is welded to the inner case. 
     
     
       6. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 5 , wherein the entirety of an opening edge of the outer case is welded to the inner case. 
     
     
       7. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 5 , wherein the inner case and the outer case are made of the same kind of metal. 
     
     
       8. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 1 , wherein the first division surface of the inner case and a second division surface of the outer case intersect with each other. 
     
     
       9. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 1 , wherein the chamber expansion has a flattened smaller dimension in a vertical direction and a larger dimension in a vehicle widthwise direction. 
     
     
       10. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 6 , wherein the first division surface of the inner case and a second division surface of the outer case intersect with each other. 
     
     
       11. An exhaust chamber, for a saddle-riding vehicle, disposed in an exhaust passage through which exhaust gas from an engine of the saddle-riding vehicle passes, the exhaust chamber comprising:
 an inner case having a chamber expansion region therein; and 
 an outer case configured to cover at least a portion of the inner case, wherein 
 the inner case has a first inner case half and a second inner case half which are obtained by division into two parts, and is formed by the first inner case half and the second inner case half being joined to each other at an inner joining portion, 
 the outer case has a plurality of outer case pieces that are spaced from each other, 
 each of the plurality of outer case pieces are joined to a portion, on an outer surface of the inner case, which portion is different from the inner joining portion, 
 the inner case includes a first portion covered by the outer case and a second portion which is not covered by the outer case, 
 the first inner case half and the second inner case half of the inner case are separable in a vertical direction, 
 center portions, in a vehicle widthwise direction, of an upper surface and a lower surface of the inner case are formed with the second portion, and 
 the outer case covers an outer side portion outward of the second portion in the vehicle widthwise direction, and is joined to the inner case. 
 
     
     
       12. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 11 , wherein a bracket for attachment to a vehicle body frame is provided in the exposed center portion of the first inner case half on an upper side. 
     
     
       13. An exhaust chamber, for a saddle-riding vehicle, disposed in an exhaust passage through which exhaust gas from an engine of the saddle-riding vehicle passes, the exhaust chamber comprising:
 an inner case having a chamber expansion region therein; and 
 an outer case configured to cover at least a portion of the inner case, wherein 
 the inner case has a first inner case half and a second inner case half which are obtained by division into two parts, and is formed by the first inner case half and the second inner case half being joined to each other at an inner joining portion, 
 the outer case has a plurality of outer case pieces that are spaced from each other, 
 each of the plurality of outer case pieces are joined to a portion, on an outer surface of the inner case, which portion is different from the inner joining portion, and 
 an endless reinforcing belt member is disposed on an inner surface of the inner case so as to extend in a direction that intersects the first division surface of the inner case. 
 
     
     
       14. The exhaust chamber for a saddle-riding vehicle as claimed in  claim 13 , wherein the endless reinforcing belt member is attached to the inner surface of the inner case by a weld to enhance rigidity of the inner case and reduce vibration sounds.